Ecolyte polymers

The rate of photodegradation of Ecolyte polymers was found generally not to be affected by the presence of antioxidants in the polymer, as the process is photolytic and not photoxidative (unless if they absorb in wavelength range that initiate degradation), but was shown to be directly proportional to the concentration of the... 

Scheme 5.2 Photooxidation of ethylene-co-vinyl ketone (Ecolyte ) polymers...

Some polymers are intentionally designed to degrade when exposed to light. There are two basic methods for doing this. One method is to incorporate a chro-mophore into the polymer chains. For example, deliberate incorporation of carbonyl groups leads to light-sensitive polymers, as in the commercial Ecolyte polymers. These polymers are made by copolymerizing vinyl ketones with vinyl monomers... 

The Ecolyte LDPE films are numbered in relation to the concentration of photosensitive vinyl ketone comonomer present in the polymer ie. 1>>2>3. The Ecolyte 1 LDPE containing the most vinyl ketone comonomer was brittle in 820 hr in the Weather-Ometer and 2.5 months outdoors. The Ecolyte 2 was brittle in Il80 hr and the Ecolyte 3 required ll+65 hr while the EcoPlastics Ltd. LDPE control required 2075 hr xenon arc irradiation to reach embrittlement. This series of Ecolytes demonstrates the varied and controlled lifetimes that can be designed into Degradable Plastics by controlling concentration of the photosensitizer. 

Major suppliers of biodegradable agents include Ampacet Corp. and Fully Compounded Plastics Inc. Major suppliers of photodegradable agents include the above and Colortech Inc., Ecolyte Atlantic Inc., and Polymer Materials Inc. 

The Ecolyte process [11] developed at the University of Toronto involves inclusion in the backbone of the chain of a polymer, of a group of the general structure... 

The photochemistry of E-CO resins is similar to that of the Ecolyte vinyl ketone copolymers except that the ketone carbonyl group is in the backbone of the polymer chain. As a result, the yield of free radicals by the type I process is very low hence the polymer does not photooxidize very rapidly and is less useful in a masterbatch application. 

Fig. 8.1. Rate of photodegradation as a function of ketone group concentration for Ecolyte S films. (Reprinted with permission from Guillet, J.E., Polymers and Ecological Problems published by Plenum Press, NY, 1973 [860].)...

Ecolyte plastics are made by copolymerizing ketone-containing comonomers in small amounts with ethylene, styrene, or other monomers used in the manufacture of commercial plastics. The process is covered by a number of patents [17]. Condensation polymers such as nylon and polyesters can also be made photodegradable by this method [18]. It is even possible with polymers such as poly(vinyl chloride) [19] and poly(acrylonitrile) [20] which normally do not degrade by chain scission. Poly(ethylene... 

Potential uses for photodegradable polymers, such as ethylene-carbon monoxide and Ecolyte polystyrene and poly(ethylene terephthalate), will exist wherever plastics littering occurs. It has been estimated that almost a billion pounds of plastics find their way into the world s waterways annually [35]. Because E-CO and foamed plastics float and are photodegradable when in water, there should be commercial opportunities for them in marine packaging, fishing gear, and similar applications. 

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